The present invention relates to a printed circuit board, and more particularly to a printed circuit board provided with a heat circulating medium, and a method for manufacturing the same.
The recent trend in the electronic industry for mounting techniques utilizes printed circuit boards (PCBs) for high density and high accuracy mounting of mounting parts employed to achieve a miniaturization and a high performance of an electronic machine. Particularly, high density PCBs capable of mounting more memory parts such as semiconductor packages are gaining attention as the chip size package (CSP) technique such as a ball grid array (BGA) and a tape carrier package (TCP) is developed. Therefore, a PCB which allows a high density mounting of memory parts is an important aspect of the technique for accomplishing a lightweight, small sized electronic machine among others such as micromachining of the part that are to be mounted on the PCB.
A PCB refers to a board having an insulation layer formed with a circuit wiring using a conductive material such as copper and accommodates mounting parts to be mounted thereon when constructing a module.
Hereinafter, a conventional PCB will be briefly described with reference to FIG. 1.
As shown, a PCB 100 includes an insulation layer 110 formed of a resin based material and a conductive circuit wiring 120. The PCB 100 has a structure in which at least one of the insulation layer 110 and the circuit wiring 120 are alternately laminated. A via type internal circuit wiring 122 is also formed in the insulation layer 110 in order to connect electrically the upper and lower circuit wirings 120, which are both disposed in the insulation layer 110. In order to form a ball land and a bump pad, the upper and lower layers of the insulation layer 110 are patterned to expose portions of the circuit wiring 120 as shown in FIG. 1.
However, in a conventional PCB as shown in FIG. 1, hot spots are generated due to the differences in the level of power consumption between parts such as the semiconductor packages that are mounted on the PCB to construct a memory module, a mother board for a PC, a graphic card for PC, and the like. Further, the circuitry malfunction may be caused by the rising PCB temperature due to the diffusion resistance resulting from the generation of hot spots. Thus, the rise of PCB temperature due to localized hot spots may lead to the system failure or poor operation of the system.
Particularly, the thermal conductivity of an insulation layer in a conventional PCB is generally low. As the conventional PCBs rely on the conductive layer that is relatively smaller in portion than the insulation layer for heat dissipation, the issue of potential system failure due to the rising temperature of the PCB will be more problematic as even greater number of semiconductor packages are mounted on a PCB in a high performance electronic machine.